Storing and shipping hydrogen peroxide



Patented Apr. 11, 1944 STORING AND SHIPYYNG HYDROGEN PERfimE Walter S. Riggs, Haddon Heights, N. 3., and Rudolf Lehmann, Hollywood, Pa assignors to The Pennsylvania Salt Manufacturing Company, Philadelphia, Pa... a corporation 02 Pennsylvania No Drawing. Application March 1'), 1M3,

Serial No. 479,508

4 Claims.

This invention relates to the passivation aluminum against attack by hydrogen peroxide.

An object of the invention is to provide a method oi treating aluminum, for example. in the term of containers, so that it will withstand attack by hydrogen peroxide.

Another object of this invention is to provide a container of hydrogen peroxide, wherein at least the interior surface of the container is made of aluminum, which may be stored and shipped without incurring any substantial loss oi hydrogen peroxide through its interaction with the container.

According to this invention aluminum is treated with a solution of sodium hydrosulilte (NilsSsOs) to render it resistant to attack by hydrogen peroxide.

The treatment is preferably applied to the depassivated metal although it may be applied to aluminum containers in which hydrogen peroxide has been shipped previously and which may or may not have been previously passivated.

The essential conditions of the treatment are time, temperature, and concentration of the solution employed.

The time 0t treatment can be varied. Treatment periods of from about hour to about forty-eight hours have been employed. Obviously the invention is not limited to any specific time range except that generally speaking longer treatment times are preferred since these result in more durable effects. In general. with higher temperatures. shorter treatment times can be employed.

The temperature of the treatment can be varied. Treatment temperatures of from about C. to about 100 C. have been employed and. in general, a temperature in the range of 35 C. to 100 C. can be employed with good results. As stated, time and temperature are dependent and compensating variables.

The .concentration of the treating solution can likewise be varied. Concentrations within the range of irom about 1% to about 25% (saturation) can be employed and, in general a concentration in the range oi. from about 5% to about will be employed.

For example. good resultshave been obtained by applying a 17% aqueous solution or sodium hydrosuliite to the aluminum at a temperature of about 8'! 0. for 8 hours. Effective results.

have been obtained with a 5% sodium hydrosulflte solution applied to the aluminum at a temperature of about 95 C. for about 1 hour. Other conditions of treatment can be employed and it is to be understood that wide variation oi. the treating conditions is possible within the scope of the claims. It is obvious that the extent of metal surface treated with a given solution will be limited by therate at which the sodium hydrosulilte becomes converted or otherwise spent in the solution. Since sodium hy-' drosulfite is easily oxidized by air, it is advisable to prevent its contact with air during the treatment.

It is preferable, when treating aluminum containers which are to be passivated, to pretreat by boiling them under reflux with a dilute sulfuric acid solution and then rinsing with water. It will be obvious that the specific treatment selected will depend upon the state of the metal prior to its treatment.

It will also be understood that various conditions will give various degrees of passivation and that those skilled in the art will be able to determine preferred treatments in each case.

We claim:

1. The process of passivating aluminum to.

0 in the range of 5% to 20%, the time oi treatment is in the range oi 54 hour to 24 hours. and the temperature is in the range of C. to 100 C.

4. The method of passlvating a hydrogen peroxide container having an interior surface of aluminum which consists in treating said sur-- face with a 17% aqueous solution of sodium hydrosulfite at a temperature 0! about 87 C. for about 6 hours.

- WALTER. 8.17.1668.

RUDOLF LEHMANN. 

